1. Field of the Invention
The present invention relates to a magnetizer and a magnetizing method.
2. Description of Related Art
A magnetizing method for magnetizing a magnet using a magnetizing yoke is known (see, for example, Japanese Unexamined Patent Publication No. H10-248216 and Japanese Unexamined Patent Publication No. H10-232141). According to the magnetizing method recited in Japanese Unexamined Patent Publication No. H10-248216 and Japanese Unexamined Patent Publication No. H10-232141, a parallel magnetic field, which is parallel to a magnetization direction, is generated around an annular magnet using a magnetizing coil and a magnetizing yoke to form two magnetic poles of different polarities, which are opposed to each other in the magnetization direction of the annular magnet. However, at the time of magnetizing the magnet, a magnetic potential (magnetization) of the magnetizing yoke is higher than a magnetic potential (magnetization) of the magnet, so that the magnetic field is disturbed due to a difference between the magnetic potential of the magnetizing yoke and the magnetic potential of the magnet. Even in a case of a magnetizing method for magnetizing a magnet 530 shown in FIG. 5 where a magnetizing yoke is not used, the above-described type of disturbance in the magnetic field occurs due to a difference between a magnetic potential of air and a magnetic potential of the magnet 530. Therefore, even when the parallel magnetic field is generated by the magnetizing coil, some magnetic lines of force are not parallel to the magnetization direction at some locations, so that the magnet cannot be magnetized with a high accuracy in the magnetization direction.